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| .. | | 03-May-2022 | - |
| include/ | H | 03-May-2022 | - | 964 | 565 |
| liba52/ | H | 03-May-2022 | - | 3,518 | 2,691 |
| libao/ | H | 03-May-2022 | - | 1,794 | 1,237 |
| src/ | H | 03-May-2022 | - | 3,032 | 2,121 |
| test/ | H | 03-May-2022 | - | 883 | 656 |
| vc++/ | H | 03-May-2022 | - | 906 | 636 |
| AUTHORS | H A D | 09-Jan-2007 | 913 | 21 | 17 |
| COPYING | H A D | 09-Jan-2007 | 17.6 KiB | 341 | 281 |
| ChangeLog | H A D | 09-Jan-2007 | 3.7 KiB | 93 | 79 |
| HISTORY | H A D | 09-Jan-2007 | 796 | 23 | 13 |
| INSTALL | H A D | 09-Jan-2007 | 92 | 6 | 4 |
| Makefile | H A D | 09-Jan-2007 | 10.8 KiB | 362 | 284 |
| Makefile.am | H A D | 09-Jan-2007 | 91 | 4 | 2 |
| Makefile.in | H A D | 09-Jan-2007 | 10.8 KiB | 362 | 286 |
| NEWS | H A D | 09-Jan-2007 | 1.1 KiB | 38 | 21 |
| README | H A D | 09-Jan-2007 | 6 KiB | 178 | 115 |
| TODO | H A D | 09-Jan-2007 | 364 | 11 | 8 |
| acinclude.m4 | H A D | 09-Jan-2007 | 2.2 KiB | 70 | 65 |
| aclocal.m4 | H A D | 09-Jan-2007 | 120.4 KiB | 3,726 | 3,330 |
| bootstrap | H A D | 09-Jan-2007 | 134 | 9 | 7 |
| config.status | H A D | 09-Jan-2007 | 22.6 KiB | 700 | 566 |
| configure | H A D | 09-Jan-2007 | 290.3 KiB | 9,827 | 8,134 |
| configure.in | H A D | 09-Jan-2007 | 3.4 KiB | 115 | 99 |
| libtool | H A D | 09-Jan-2007 | 146.2 KiB | 5,316 | 4,120 |
README
1
2
3ABOUT LIBA52
4
5liba52 is a free library for decoding ATSC A/52 streams. It is
6released under the terms of the GPL license. The A/52 standard is used
7in a variety of applications, including digital television and DVD. It
8is also known as AC-3.
9
10The main goals in liba52 development are:
11
12 * Portability - Currently all of the code is written in C, and
13 when we write platform-specific optimizations we will always
14 keep a generic C routine to fall back on.
15
16 * Reuseability - we do not want liba52 to include any
17 project-specific code, but it should still include enough
18 features to be used by very diverse projects.
19
20 * Precision - We are trying to implement all of the A/52
21 standard, and to have a very precise output by doing all the
22 calculations in floating point. We have a test suite that
23 detects any deviation in the output when compared to previous
24 versions. We do not have access to official A/52 test vectors
25 though, so we have to use our judgement to ensure that such
26 deviations are only intruduced when we fix bugs !
27
28 * Speed - liba52 is really fast, on any modern PC it should take
29 only a few percent of CPU time.
30
31The project homepage is at http://liba52.sourceforge.net/
32
33
34A52DEC
35
36a52dec is a test program for liba52. It decodes ATSC A/52 streams, and
37also includes a demultiplexer for mpeg-1 and mpeg-2 program streams.
38
39The liba52 source code is always distributed in the a52dec package, to
40make sure it easier for people to test it.
41
42The basic usage is to just type "a52dec file" where file is an ATSC
43A/52 file.
44
45The "-s" option must be used for multiplexed (audio and video) mpeg-2
46files. These files are usualy found on the internet or on unencrypted
47DVDs.
48
49The "-o" option is used to select a given output layer. By default
50a52dec does a stereo downmix and outputs to your speakers, but you can
51try other choices using this option. This is also used for performance
52testing and conformance testing.
53
54The "-c" option is used to disable all optimizations (currently only djbfft).
55
56The "-r" option is used to disable the dynamic range compression.
57
58
59OTHER PROJECTS USING LIBA52
60
61liba52 (and its ancestor libac3) is being used by various other
62projects, including:
63
64 * xine (http://xine.sourceforge.net/) - started as a simple
65 mpeg-2 audio and video decoder, but it since became a
66 full-featured DVD and video media player.
67
68 * MPlayer (http://www.MPlayerHQ.hu) - another good player, it is
69 also very robust against damaged streams.
70
71 * movietime (http://movietime.sourceforge.net/) - still quite
72 young, but it looks very promising !
73
74 * ffmpeg (http://ffmpeg.sourceforge.net/) - a nice audio/video
75 encoder and transcoder, uses liba52 for decoding A/52 streams.
76
77 * Ogle (http://www.dtek.chalmers.se/groups/dvd/) - a good DVD
78 player with menu support
79
80 * OMS (http://www.linuxvideo.org/oms/)
81
82 * XMPS (http://xmps.sourceforge.net/)
83
84 * GStreamer (http://www.gstreamer.net/) - a framework for
85 streaming media; it has an A/52 decoding plugin based on liba52.
86
87 * mpeglib (http://mpeglib.sourceforge.net/) - a video decoding
88 library that usess liba52 when decoding A/52 streams.
89
90If you use liba52 in another project, let us know !
91
92VideoLAN (http://www.videolan.org/) does not use liba52, but this is
93still a cool project :)
94
95
96TASKS
97
98There are several places where we could easily use some help:
99
100 * Web design: This site sucks ! at the very least, we'd like to
101 come up with a nicer background picture and a logo.
102
103 * Testing: If you find any stream that does not decode right
104 with liba52, let us know ! The best thing would be to mail to
105 the liba52-devel mailing list. Also if you have access to
106 encoders, we'd love to get test streams that would be free of
107 rights - so that we can put them on this server.
108
109 * Coding: you can have a look in the TODO file first ! The most
110 important item is probably to make the code fully reentrant.
111
112 * Porting: If you're porting to a new architecture, you might
113 want to experiment with the compile flags defined in
114 configure.in . When you figure out whats fastest on your
115 platform, send us a patch !
116
117
118REFERENCES
119
120The A/52 standard is publically available at these locations:
121
122 * http://www.atsc.org/standards/a_52a.pdf - The main part of the
123 standard, as published by the ATSC.
124
125 * http://www.dolby.com/tech/ATSC_err.pdf - A list of erratas in
126 the ATSC standard, published by Dolby. It applies to the
127 previous revision of the standard (A/52 not A/52a), but some
128 erratas have not been fixed in the updated standard yet !
129
130
131CVS SNAPSHOTS
132
133A daily snapshot is created using "make distcheck" every night and
134uploaded to http://liba52.sourceforge.net/files/a52dec-snapshot.tar.gz .
135It is easier to use than the CVS repository, because you do not need
136to have the right versions of automake, autoconf and libtool
137installed. It might be convenient when working on a liba52 port for
138example.
139
140
141CVS REPOSITORY
142
143The latest liba52 and a52dec source code can always be found by
144anonymous CVS:
145
146# export CVSROOT=:pserver:anonymous@cvs.liba52.sourceforge.net:/cvsroot/liba52
147# cvs login (Just press Return when prompted for a password)
148# cvs checkout a52dec
149
150You can also browse the latest changes online at
151http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/liba52/a52dec/
152
153The other CVS modules are ac3dec-livid for the CVS history of the
154project while it was still hosted on the linuxvideo.org servers, and
155ac3dec for the CVS history of the project while the linuxvideo.org
156servers were down and before the library switched its name to liba52.
157
158
159MAILING LISTS
160
161See the subscription information at http://liba52.sourceforge.net/lists.html
162
163liba52-devel
164
165This is the main mailing list for technical discussion about
166liba52. Anyone wanting to work on liba52, or maybe just stay informed
167about the development process, should probably subscribe to this list.
168
169liba52-checkins
170
171All liba52 checkins are announced there. This is a good way to keep
172track of what goes into CVS.
173
174liba52-announce
175
176This is a very low traffic mailing list, only for announcements of new
177versions of liba52. Only project administrators can post there.
178